Integrated Moving-Bed and Ebullating-Bed Hydroconversion Process
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Solution Overview
Problem
Fixed-bed reactors become ineffective and costly when processing heavy hydrocarbon feeds with high metal content, leading to rapid deactivation and increased coke formation, while ebullating-bed reactors maximize conversion but compromise refining performance.
Innovation Solution
A process integrating moving-bed and ebullating-bed technologies, where a moving-bed reactor with semi-continuous catalyst renewal is used upstream of an ebullating-bed reactor, allowing for controlled catalyst circulation and hydrogen quenching to enhance refining and conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fixed-bed reactors are used for processing heavy hydrocarbon feeds with high metal content, then high refining performance is obtained, but the reactors quickly become deactivated due to metal accumulation and coke formation
Solution Approach 1:
The patent applies moving-bed technology where the catalyst bed is in continuous motion rather than stationary, allowing spent catalyst to be continuously removed and fresh catalyst added. This dynamic approach prevents metal accumulation and coke formation that would otherwise deactivate fixed-bed catalysts, extending operating time while maintaining refining performance
Solution Approach 2:
The moving-bed system continuously discards spent catalyst that has accumulated metals and coke, replacing it with fresh catalyst. This prevents catalyst deactivation and maintains high refining performance over extended operating periods without the need for reactor shutdowns
2Productivity
If ebullating-bed reactors are used to maximize conversion of heavy feeds, then conversion efficiency increases, but refining performance deteriorates
Solution Approach 1:
The patent segments the conversion process into two distinct stages: first a moving-bed reactor for hydrorefining that removes impurities, then an ebullating-bed reactor for hydroconversion that maximizes conversion. This segmentation allows each reactor type to optimize its specific function without compromising the other
Solution Approach 2:
The moving-bed reactor performs preliminary refining by removing metals, sulphur, and nitrogen before the feed enters the ebullating-bed reactor. This preliminary action protects the second reactor from catalyst poisoning while maximizing conversion of the pre-refined feed
3Manufacturing precision
If fixed-bed reactors process feeds with high metals content (100-150 ppm), then initial refining performance is maintained, but operating time decreases due to rapid catalyst deactivation
Solution Approach 1:
The moving-bed system continuously repositions and renews the catalyst bed, preventing the accumulation of metals and coke that would otherwise quickly deactivate the catalyst. This dynamic renewal extends operating time from months to years while maintaining consistent refining performance
Solution Approach 2:
The moving-bed reactor enables continuous operation by continuously removing spent catalyst and adding fresh catalyst without shutting down the unit. This continuity eliminates the 3-6 month shutdown cycles required for catalyst replacement in fixed-bed systems
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This integrated process maximizes feed refining and conversion while minimizing catalyst consumption and maintaining high product quality, overcoming the limitations of both individual technologies.
Implementation Method 1
a moving-bed reactor with semi-continuous catalyst renewal is used upstream of an ebullating-bed reactor, allowing for controlled catalyst circulation
Implementation Method 2
allowing for controlled catalyst circulation and hydrogen quenching to enhance refining and conversion efficiency
Implementation Method 3
ebullating-bed reactor, allowing for controlled catalyst circulation
Data Source
AI summary
The invention describes a process for the conversion of heavy carbon-containing fractions having an initial boiling point of at least 300° C. to upgradable lighter products, said process comprising passage of said feed through a hydrorefining reaction zone comprising at least one moving-bed reactor, and passage of at least a portion of the effluent from stage a) through a hydroconversion reaction zone comprising at least one three-phase reactor, in the presence of hydrogen, said reactor containing at least one hydroconversion catalyst and operating in ebullating-bed mode, with an ascending current of liquid and gas and comprising at least one means of withdrawing said catalyst out of said reactor and at least one means of adding fresh catalyst into said reactor, under conditions making it possible to obtain a liquid feed with a reduced content of Conradson carbon, metals, sulphur and nitrogen.